The first wave of Firefox OS devices will be available to consumers in Brazil, Colombia, Hungary, Mexico, Montenegro, Poland, Serbia, Spain and Venezuela in the coming months, with additional mobile markets to follow.

Firefox OS smartphones are built on open web standards, enabling various features to be developed as HTML5 web applications.

This means that carriers can more easily tailor the interface to their needs, as well as offer services localised to certain markets or customer segments.

"Firefox OS brings the freedom and unbounded innovation of the open web to mobile users everywhere," said Gary Kovacs, the chief executive of Mozilla.

"With the support of our vibrant community and dedicated partners, our goal is to level the playing field and usher in an explosion of content and services that will meet the diverse needs of the next two billion people online."

Mozilla has also announced its new branding for Firefox OS - using the slogan "Unleash the Fox" to illustrate "the qualities of Firefox OS: fun and friendly; supportive and protective; fast and powerful".

Telefónica will be among the first operators to launch Firefox OS, starting in Brazil, Colombia, Spain and Venezuela, but with a view to making it eventually available to "all Telefonica customers globally".

Cesar Alierta, the chairman & chief executive of Telefónica, said that 2013 in the mobile industry will be "characterised by open standards".

"For Telefónica and the telco sector as a whole, Firefox OS is a hugely important strategic initiative to change the prevailing value chain in the digital world," he said.

"It is a major step to bring balance back to the telco sector, an initiative with strong cross-industry support.

"I am very pleased that our customers in Brazil, Colombia, Spain and Venezuela will be amongst the first in the world to experience Firefox OS and I look forward to making it available to all Telefónica customers globally."